Larry Niven’s Ringworld was published in 1970 and immediately became one of the standards for which to compare other superstructures to. In the story, a gargantuan ring is explored by the long lived Louis Wu, the lucky Teela Brown, the insane Nessus, and the ferocious Speaker-to-Animals. Being a million miles across, with a diameter of 186 million miles, the protagonists can only look over a small fraction of Ringworld’s surface. The gravity of Ringworld is approximately 99.2% of Earth. Despite this similarity to Earth’s gravity, Ringworld’s genesis can be found not with humans, but with the Pak Protectors. This species is considered the precursor for humanity and the rest of the hominids on Ringworld.

In Engineers of Ringworld, a book originally written because of the engineering constraints criticized in the first, Niven shows how there are a series of thrusters around Ringworld to keep it in orbit. Because of the extinction of the Pak Protector, there has been nobody around for millions of years to keep up the machines, resulting in a steady failure of one thruster after another. This fluctuation is practically unfelt on the surface, with a more notable feature being the imposing shadow squares. These enormous panels simulate the night and day cycle, but differ in many ways from natural rotation. Spanning over a set area in thirty hour increments, the shadow squares give absolute darkness and light, with only minutes between the sun setting and rising. All of this is held together with the fantastical scirth, a frictionless material that absorbs 100% of all forms of radiation. Scirth is so powerful that it has a tensile strength equivalent to the strong nuclear force. Without this imaginary super substance, Ringworld’s tidal forces would rip itself apart.

In order to keep the Earth like atmosphere on this superstructure, the Pak Protectors put 1000 mile high walls along the perimeter. Despite these precautions, when Louis Wu and the rest of the expedition enter Ringworld, they discover it in a slow decline. Because of this, weather patterns have been greatly upset by the decaying machines. Around the perimeter is a set of lasers to ward off asteroid impacts. One set of these lasers failed, resulting in a crater on the back end of Ringworld. From the expeditions standpoint, this was the impossibly colossal mountain the natives dubbed “Fist of God”. The Fist of God further disrupted wind patterns and led to a never ending super hurricane.

Could this be built?

A far advanced society that somehow controls a substance with the same tensile strength of the Strong Nuclear Force could potentially create such a structure. First, a stable star would be needed, along with plenty of material. Think on the level of ripping apart entire solar systems to create the 600 million mile diameter that is Ringworld. From here, the creators would need a considerable amount of time that would consume the course of several human long lifespans. As seen with the intermittent failures of Ringworld’s machine, there would need a tremendous amount of upkeep. Asteroid impact, drifting into the sun, keeping the environment sustainable for life, along with a thousand other problems would plague this theoretical superstructure.

A smaller version called Halos can be found in the video game Halo: Combat Evolved. This smaller type was built by a more advanced alien species, using it as an artificial environment to study the parasitic species called the Flood. Like its larger cousin, this miniature Ringworld would suffer from destructive tidal forces, unstable orbit, and prone to meteorite impact. Spectroscopic analysis within the game’s universe seem to imply that the halo is composed of an exotic substance akin to scirth. This version of the Ringworld would consume much less in terms of resources and could potentially be built over the course of several decades rather than centuries.

A fantasy based variety is found atop the Spire in the Dungeon’s and Dragons universe. Around the inner rim of the torus shape is the city of Sigil. Sigil serves as a hub of different realities and worlds – a neutral area were those of opposing alliances and species can coexist peacefully. The city of Sigil has multiple paradoxes – such as existing on an infinite expanse, while at the same time said to be at the center. Infinity, when put on a spatial dimension, does not have a center by nature. Much of this is explained by the in game lore of magic and wizardry. This fantastical foundation renders the city of Sigil one of the most imaginative, yet impossible, structure’s in literature.

In the end, even Larry Niven admitted that there was little reason to build Ringworld in light of so many more practical ideas. Nonetheless, it makes for an interesting story – and it is in this that the power of Ringworld becomes so important. Such a superstructure will probably never exist, yet it has left a permanent mark on the psyche of science fiction fans, and thus, humanity as whole.